A stent is a generally tubular device that is used to support a bodily lumen. A stent is typically delivered to a desired bodily location via a catheter.
Magnetic resonance imaging (MRI) has been widely used to image various parts of the body. One of the uses of MRI has been to image blood flow. It is, therefore, desirable for stents to be MRI compatible to allow for imaging of vessels in the region of a stent. Although there has been a great deal of activity focusing on the choice of materials for MRI compatible stents, other factors in the design of the stent must be considered as well.
For example, a stent that is made from an electrically conductive material that is formed in electrically conductive loops which extend fully around the longitudinal axis of the stent, as shown by way of example at 50 in FIG. 1, may facilitate the formation of eddy currents when the region of the body in which the stent is located is imaged. Similarly, the presence of closed, electrically conductive loops which extend in a longitudinal direction in the wall, as shown by way of example at 54 in FIG. 1, also may result in eddy currents. Eddy currents, however, are know to cause distortions in MRI images.
While many helical stents avoid the problem of electrically conductive loops which extend fully about the longitudinal axis, helical stents may have less compression resistance as compared with stents having circumferential bands which extend fully about the longitudinal axis. The scaffolding provided by helical stents is also less than that provided by many of the stents having closed circumferential bands.
Generally, there is a tradeoff between scaffolding and side branch access. A stent with a larger, more open geometry will have an improved side branch access and expandability but poorer scaffolding. Smaller, tight geometry results in better scaffolding, but poor side branch access and expandability.
There remains a need for MRI compatible stents with innovative designs which combine excellent scaffolding, compression resistance and side branch access while at the same time providing reduced MRI distortions.
All US patents, applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
A brief abstract of the technical disclosure in the specification is provided as well only for the purposes of complying with 37 CFR 1.72.